Optical, Electrochemical and Thermal Studies of Conjugated Polymers Synthesized by Eutectic Melt Reaction

This paper reports on the synthesis of a novel donor-acceptor conjugated polymers, P1 and P2 by solvent free eutectic melt polymerization reaction. Triisopropylsilylethynyl(TIPS) substituted benzo[1,2-b:4,5-b']dithiophene(BDT) is used as donor, thienithiophene(TT) and thienopyrroledione(TPD) are utilized as acceptors for demonstrating eutectic polymerization. The most important fact in the solvent-free reaction between solid reactants actually proceeds through bulk liquid phases. Such liquid phases are possible due to the formation of eutectics between the reactants and product(s) and any evolution of heat. Naphthalene is explored in this reaction for forming eutectics with the reactants, resulting in desired polymers. Thermal stability, optical and electrochemical properties of these polymers were determined. Optical band gaps of the polymers were found to be 1.58 and 1.65 eV. Electrochemical studies by cyclic voltametry experiment revealed HOMO and LUMO energy levels to be -5.22, -5.60 eV, and -3.76, -4.16 eV, respectively. The polymers were thermally stable up to 285-400 °C. Thermal, optical and electrochemical studies indicated these materials to be promising candidates in organic electronic applications.

Synthesis, Characterization and Optoelectronic Properties of Benzodithiophene Based Copolymers for Application in Solar Cells

This paper reports on the synthesis and characterization of novel donor-acceptor (D-A) conjugated polymers containing triisopropylsilylethyny(TIPS)benzo[1,2-b:4,5-b']dithiophene-diketopyrrolopyrrole (P1 and P2) through Stille co-polymerization method. Thermal stability, optical and electrochemical properties of these polymers were determined. Optical band gaps of the polymers as calculated from their film onset absorption edges were found to be 1.46 and 1.44 eV, respectively. Electrochemical studies revealed HOMO and LUMO energy levels to be -5.22, -5.60 eV, and -3.76, -4.16 eV, respectively. The polymers were thermally stable up to 400-440 °C. Optoelectronic studies indicated that these materials to be promising candidates in solar cell applications.

Donor–acceptor conjugated polymers based on multifused ladder-type arenes for organic solar cells

In this review, we summarize the recent development of the multifused ladder-type conjugated building blocks for making donor–acceptor conjugated copolymers.

Naphthodithiophenes: emerging building blocks for organic electronics

Linear-fused naphthodithiophenes (NDTs) are emerging building blocks in the development of new semiconducting small molecules, oligomers, and polymers. The promising nature of NDT-based materials as organic semiconductors has been demonstrated by superior device characteristics in organic field-effect transistors (OFETs) and organic photovoltaics (OPVs) in the last few years. In particular, it is quite impressive that a power conversion efficiency as high as 8.2% has been achieved for a single-junction OPV cell consisting of NDT-based semiconducting polymers and a fullerene derivative in such a short period of time. Here, we provide an overview of recent synthetic evolutions in NDT chemistry and progress in NDT-based materials, especially conjugated oligomers and polymers and their applications to OFETs and OPVs.